Process for the reduction of the sulfur content in a gaseous stream

Abstract

A process for the reduction of sulfur content in gas streams with production of elemental sulfur wherein the sulfur-containing gas is thermally treated, in the presence of oxygen, with a catalyst consisting essentially of titanium oxide.

What is claimed is: 
     
       1. A process for the reduction of sulfur content in a gaseous stream with the production of elemental sulfur, comprising the steps of: (a) treating the gaseous stream by at least one of hydrogenation and hydrolysis to convert substantially all of the sulfur components therein to hydrogen sulfide;   (b) then reducing the water content of the gaseous stream to less than 10 volume percent;   (c) introducing oxygen into the gaseous stream;   (d) treating the gaseous stream in a first oxidation reactor, containing a catalyst comprising at least 80 percent by weight titanium dioxide, at a temperature of about 200° C. to 270° C. wherein substantial conversion of H 2  S to elemental sulfur occurs;   (e) cooling the product gas to a temperature of 120°-140° C. to separate elemental sulfur by condensation;   (f) introducing additional oxygen into the gaseous stream in substantially stoichiometric amounts based on the sulfur content; and   (g) treating the gaseous stream in a second oxidation reactor, containing a catalyst comprising at least 80 percent by weight titanium dioxide, at a lower temperature than that utilized in the first oxidation reactor.   
     
     
       2. The process of claim 1 wherein the H 2  S/O 2  ratio in th gaseous stream introduced into the first oxidation reactor is controlled such that the non-converted sulfurs in the product gas consist essentially of H 2  S. 
     
     
       3. The process of claim 1 wherein the catalyst in the oxidation reactors comprises 5 to 20 percent by weight earth alkaline metal sulfates. 
     
     
       4. The process of claim 1 wherein the temperature of the second oxidation reactor is from about 190° C. to about 240° C. 
     
     
       5. The process of claim 1 wherein the H 2  S/O 2  ratio in the gaseous stream introduced into the second oxidation reactor is controlled such that the non-converted sulfurs in the product gas consist essentially of H 2  S and SO 2  in the ratio of 2 to 1, respectively. 
     
     
       6. The process of claim 1 wherein the gaseous stream of step (d) is cooled down to a temperature of about 125° C. to 135° C. 
     
     
       7. The process of claim 1, wherein the water in the gaseous stream is reduced to about 4-6 volume percent in step (b). 
     
     
       8. The process of claim 1 wherein the gaseous stream is passed through the first reactor, containing the catalyst, at a space velocity of about 500 to 3000 h -1  relative to the normal state. 
     
     
       9. The process of claim 8 wherein the space velocity is about 800 to 1500 h -1 . 
     
     
       10. The process of claim 1 wherein the catalyst has a specific surface area of 80-150 m 2  per gram and a total pore volume of approximately 0.30-0.45 cm 3  per gram. 
     
     
       11. The process of claim 1 wherein additional components in the gaseous stream, such as light saturated hydrocarbons, hydrogen, or carbon monoxide, are not oxidized. 
     
     
       12. The process of claim 1 wherein the gaseous stream contains as sulfur compounds H 2  S, SO 2 , COS, CS 2 , CH 3  SH, sulfur vapor or any combination thereof.